A conventional method of setting the optimum recording power is disclosed in an unexamined patent publication JP 7-73468, published Mar. 17, 1995. This publication discloses a control method for minimizing the difference between a peak level obtained from the amplitude of a retrieved signal of an isolated mark pattern and a peak level obtained from the amplitude of a retrieved signal of a repeated mark pattern. Thus, this method, referred to as "test write record control" is realized by setting an optimum recording power by recording predetermined data on an optical disk and retrieving the recorded data.